Supraventricular Arrhythmias and Treatment

The objective of this article is to review supraventricular arrhythmias emphasized the importance of atrial fibrillation (AF) and its novel therapeutic approach in dogs. Supraventricular arrhythmias include disturbances of impulse formation at sinus node, atria and junctional area or alterations of impulse conduction within the chamber above ventricles. Among those supraventricular arrhythmias, AF is the most commonly seen supraventricular arrhythmias in veterinary practice. While APC, AT, atrial flutter, re-entrant supraventricular tachycardia, and atrial standstill are relatively uncommon in veterinary patients. AF contributes to increase mortality through its associations with cardiomyopathy or valvular heart disease. Current therapies of canine AF are limited by their efficacy and adverse effects, including proarrhythmic effects or by their adverse effects to other organs. These limitations are necessary to select novel pharmacological therapy to expand the treatment options in AF dogs. Dronedarone is a benzofuran derivative that was synthetized based on amiodarone, but has some structural changes to avoid adverse effects. Recent studies showed that oral dronedarone (20 mg/kg BID, 7 days) can attenuate the duration of sustained AF in canine AF model without effect on cardiac inotropy or lusitropy. Clinical trials of dronedarone in clinical AF dogs are challenges for the future. Introduction Supraventricular arrhythmias are defined as one of the rhythm disturbances that originate in the upper chambers of the heart. Supraventricular arrhythmias include sinus rhythm disturbances (i.e. sinus tachycardia, sinus bradycardia, sick sinus syndrome, sinus arrest and sinoatrial exit block), atrial rhythm disturbances (i.e. atrial fluster, atrial fibrillation, atrial premature complex) and junctional rhythm disturbances (i.e. premature junctional complexes). Atrial premature complexes (APC), atrial tachycardia (AT), atrial flutter, atrial fibrillation (AF), re-entrant supraventricular tachycardia, and atrial standstill are atrial rhythm disturbances. These arrhythmias can be transient, recurrent, or permanent. In most cases recurrent or permanent arrhythmias are associated with structural heart diseases such as chronic valvular disease